About Us: Seminars

Spring 2007 Seminars

Seminars
are held on Tuesdays, 3:45-4:45pm in SB110, unless otherwise noted. Meet
at 3:30 in SB157 for refreshments (refreshments are available even on
Tuesdays with no seminar!). See Calvin's
Visitor Resources for maps and directions to the Science Building.

Date

Title

Speaker

Friday, February 2, SB010 (sponsored by
the Christian Perspectives in Science series and the Calvin Philosophy Department)

February 20: Sabbatical Report: Distant Galaxy Clusters Prof. Deborah Haarsma, Calvin College Galaxy clusters are the most massive gravitationally-bound objects in
the universe, with thousands of galaxies which each contain billions
of stars. We recently identified 5-7 new galaxy clusters located
billions of lightyears away, among the most distant clusters detected
to date. Such clusters are key to addressing several questions in
modern astrophysics, including galaxy formation in the densest regions
of the universe, the role of feedback from quasars and stellar winds,
the role of galaxy mergers, and the history of star formation. The
new clusters will be studied with telescopes across the spectrum to
understand their properties and address these questions.

March 6: A New Era of Gamma-Ray PulsarsSarah Story and Prof. Peter Gonthier, Hope CollegeSince their initial discovery in 1967, more than 1600 pulsars, including about 150 ultra-fast millisecond pulsars, have been discovered, mostly by ground-based radio telescopes. The launch of the Compton Gamma-ray Observatory (CGRO) in 1991 made it possible to detect gamma-ray emission from six gamma-ray pulsars with high confidence and a few others with lower confidence, including a binary millisecond pulsar with a rotational period of 2.3 ms and an orbital period of 2.03 days. EGRET, the instrument aboard CGRO that was sensitive to pulsars, could only detect pulses from the brightest gamma-ray pulsars. Now, new instruments promise to revolutionize our understanding of high-energy emission from pulsars by dramatically increasing the number of known gamma-ray pulsars. AGILE, an Italian satellite, will be launched at the end of the month, and GLAST, a collaboration between NASA and European space agencies, is scheduled for launch in the fall. We attempt to understand the geometry and luminosity of radio and gamma-ray emission from pulsars by simulating the characteristics of these beams and predicting their detectability by radio surveys as well as by the gamma-ray instruments EGRET, AGILE and GLAST. By exploring the correlations of the radio and gamma-ray beams, we try to pinpoint the location within the magnetosphere of the region producing the gamma-ray emission. We present some results of our population statistics synthesis of radio and gamma-ray pulsars, which include both normal and millisecond pulsars, and make predictions for AGILE and GLAST.

April 3: Formation of the Biggest Galaxies in the Universe: Winds and Shocks
from Black Holes in the Centers of Clusters of GalaxiesProf. Megan Donahue, Michigan State UniversityI will discuss the connection between the supermassive black holes that
grow in the centers of the most massive galaxies in the universe and
their
host cluster of galaxies. The X-ray-emitting atmosphere in a cluster
of galaxies --
the hot gas between the galaxies, bound to the cluster by gravity --
holds many clues about the nature of the energy emerging from the region
surrounding the central supermassive black hole. This relationship
may be
the answer to many questions about how galaxies form, why supermassive
black holes get bigger in bigger hosts, and how diffuse gas behaves
in gravitational
potentials of dark matter halos that have a quadrillion times the
mass of the sun.

April 12: Opening Scientific Doors with Art and HistoryDr. Marvin Bolt '84, Adler Planetarium and Astronomy MuseumIn October 2006, Calvin physics alum Marvin Bolt discovered two of
the oldest telescopes in the world hidden away in storage in German museums. Join us for a European tour that involves physics,
art history, cultural history, theology, and politics to increase our
understanding of the early history of the telescope.

April 27: Driftsondes: Looking for Data in All the Remote PlacesJoseph Van Andel '78, National Center for Atmospheric ResearchJoe Van Andel
will discuss the NCAR/CNES dropsonde project that investigated the
hurricane formation zone off the west coast of Africa.

NCAR worked with the French Space Agency (CNES) to create and carry a
payload that would float west from Africa into the hurricane formation
zone. The balloon floated at 20,000 meters and higher, which is above
the tropopause, the altitude at which the troposphere (where most of our
weather takes place) gives way to the stratosphere. Each gondola
consisted carried an array of 24 to 40 dropsondes beneath it. On
command, the gondola would drop the sonde, receive 20-30 minutes of
atmospheric data, and then send this data to the project office.

Joe will present an introduction to the driftsonde project,
discuss the scientific goals of driftsondes, and show some of the data
generated by last summer's driftsonde experiment.
He'll discuss how driftsonde data could eventually improve long range
forecasts,
and possibly reduce deaths and injuries caused by severe weather events.

May 8: Fermilab - Life on the Frontier of PhysicsClark Cully '03, University of MichiganEveryday at Fermilab, the world's largest particle
accelerator, we hurl matter and antimatter into each other an nearly
the speed of light. The resulting collisions are so intense as to
convert energy directly to mass, thus producing rare particles not
seen since the Big Bang. We hope to see the signature of new forms of
matter, new fundamental forces, or maybe even new dimensions of space.
Over a thousands physicists are racing to make the next big discovery
before Europe's new more powerful machine, the Large Hadron Collider,
comes online and ends our search.